This invention relates to a thermoplastic composite composition comprising (I) a thermoplastic material and (II) a polyolefin composition containing specific reactive inorganic filler at a high concentration.
Polymer blending is a known method for improving the properties of plastics, and polyolefins are polymers useful for polymer blending. In general, when two or more polymers are mixed to produce a polymer blend the melting point of the resulting polymer blend decreases in accordance with Flory's equation, and as for other physical properties the polymer blend usually exhibits the defects of the polymers mixed. Therefore, only few polymer blends are suited for practical uses. Even if a polymer blend is successfully obtained, the amount of a polymer to be incorporated therein is generally small and the optimum mixing ratio from the point of view of coupling the maximum improvement in the properties in the resulting polymer blend with the minimum sacrifice in the properties is in a narrow range. This tendency is remarkably observed on the polymer blends of crystalline polymers or polar polymers with polyolefins. Factors such as low compatibility between the polymers mixed, non-ununiformity of the dispersion due to the difference in melting viscosity of the polymers mixed, non-uniformity of cooled and solidified state and great residual stress due to the difference in melting point, coefficient of thermal contraction, coefficient of linear expansion and specific heat of the polymers mixed, and non-uniformity of stress distribution due to the difference in rigidity of the polymers mixed are considered to disadvantageously influence on the moldability, external apperance of molded articles and properties, especially mechanical strength of polymer blends.
Methods of overcoming these disadvantages are already available. British Patent Nos. 998,439 and 1,194,453 relate to the polymer blending of a polar polymer with a non-polar polymer, and in order to improve the compatibility of the polymers to be mixed the non-polar polymer is copolymerized with a polar monomer. Japanese Patent Publication No. 41456/1971 decribes the control of the liquid state of polymer blends by extremely varying melting viscosities of the polymers mixed. According to these methods, however, mechanical strength, rigidity, thermal resistance and creep greatly deteriorate. This suggests that by the improvement in compatibility alone or in liquid state alone full and sufficient effects of polymer blending cannot be obtained and there are some other factors which influence on polymer blends. In now pending application Ser. No. 316,314, filed Dec. 18, 1972 by the present applicants plus others there are disclosed thermoplastic compositions comprising about 15 to 90 percent by weight of a thermoplastic material and about 85 to 10 percent by weight of at least one reactive inorganic filler, said reactive inorganic filler having been prepared by effecting reaction between an inorganic material and an unsaturated aliphatic or aromatic carboxylic acid with stirring in the absence of liquid-form water in the powder state.